1. Technical Field of the Invention
The present invention relates to drugs and methods for treating heart disease using benzopyran derivatives and salts thereof.
2. Background Art
The present inventors have previously reported on the anti-allergy effect of benzopyran derivatives in International Patent Publication No. WO 92/13852, Japanese Patent Application, First Publication No. Hei 8-198890 and U.S. Pat. No. 5,428,059, the disclosure of which is incorporated herein by reference.
Compounds corresponding to the benzopyran derivatives of the present invention have been described in U.S. Pat. No. 4,845,121 and Donald T. Witiak, J. Med. Chem., vol. 31, p. 1437-1445, 1988. However, these benzopyran derivatives and physiologically acceptable salts thereof have conventionally not been known to be effective in treating heart disease.
Additionally, benzopyran derivatives wherein the 7-position substituent group is an alkyl group having at least one hydroxyl group and physiologically acceptable salts thereof are compounds which the present inventors have newly synthesized as a result of synthesizing numerous types of benzopyran derivatives and analyzing them for the purposes of offering an effective method of treating heart disease, and their pharmacological effects have been conventionally unknown.
Although numerous pharmaceuticals for treating ischemic heart disease and arrhythmia have been available on the market, they are prone to having severe side effects, especially the medications for treating arrhythmia for which the difference between an effective dose and a toxic dose is small, thus making their therapeutic use difficult.